The present invention is related to a printed circuit board (PCB), and more particularly to a multiple layer module structure taking into account impedance, noise and signal interference.
In general, a multi-layer module for PCB in a direct Rambles Rim module which includes eight layers and is designed by taking into account impedance, noise and signal interference. For example, as shown in FIG. 1, a PCB multiple layer module 1 for a PCB including eight layers comprises a first layer 11 formed as an uppermost layer and which components are disposed therein, a second layer 12 for matching the impedance of the first layer 11 and protecting signals from the noise and interference, a third layer 13 for receiving and outputting signals which is disposed under the second layer 12, a fourth layer 14 which the power Vdd is supplied thereto and is disposed under the third layer 13 as a power layer, a fifth layer 15 which is disposed under the fourth layer 14 as a ground layer, a sixth layer 16 for receiving and outputting signals which is disposed under the fifth layer 15, a seventh layer 17 which is disposed under the sixth layer 16 as a ground layer and an eighth layer 18 which is disposed under the seventh layer 17.
In the prior 8-layer module 1, the second layer 12 is formed as a ground layer under the first layer 11 so as to prevent the noise and signal interface between components disposed in the first layer 11. The second layer 12 which is a ground layer and the fourth layer 14 which is a power layer, are disposed above and below the third layer 13 which receives and outputs the signals. The fifth layer 15 and the seventh layer 17 which are ground layers, are disposed above and below the sixth layer 16 which receives and outputs signals. The eighth layer 18 which is a lowermost layer, is disposed below the seventh layer 17 which is a ground layer.
That is, the layers disposed above and below the layer where components are disposed or the signals are received and outputted, are wrapped in copper so as to prevent interference and match the impedance therebetween. In other words, so as to prevent the signal interference and the noise of the layers, it made the second layer 12 as a ground layer wrapped in copper. The second layer 12 as a ground layer and the fourth layer 14 as a power layer which are disposed below and above the third layer 13 respectively, are wrapped in copper and the fifth layer 15 and the seventh layer 17 which are disposed respectively as a ground layer below and above the sixth layer 16, are wrapped in copper. In the eighth layer 18, only the signal lines are wrapped in copper.
However, the prior multiple layer module has a disadvantage that it is constituted in eight layers so that the fabrication process is complicated and the yield is degraded.